Hey what's up note u have nothing to worry about as per GM the 9-7x's will loose a quart for every 5k mile or so, so as per GM again this is consider normal for the v8's, just a heads up if have not cleaned your throttle housing, I recommend you getting it done, may set fault code & leave u on the side of the road, vehicle loosing power, note this is just some helpfull info, cause I work on them everyday. Good luck.